Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W28/00—Network traffic management; Network resource management
  • H04W28/02—Traffic management, e.g. flow control or congestion control
  • H04W28/06—Optimizing the usage of the radio link, e.g. header compression, information sizing, discarding information

Definitions

• the present invention relates to a method of transmitting data in non-connected mode by a mobile station comprising a step of determining the maximum size of data packet transmission, known as MDS for Maximum Datagram Size in English (or MMDS). for Mobile MDS).
• the invention relates to the field of communications made from a mobile station within the framework of the GSM standard.
• a mobile station is made up of mobile equipment and a smart card known as a SIM (for Subscriber Identification Module) card.
• the mobile equipment can be a telephone, a personal digital assistant (PDA) or other.
• PDA personal digital assistant
• the communications in question within the framework of the present invention can be communications between two mobile stations or between a mobile station and a remote server capable of communicating with such a mobile station, such as for example a communication gateway better known by the term OTA server (Over The Air in English).
• OTA server Over The Air in English
• the communication protocols used in particular in a wireless communication context are the suite of WAP protocols (for Wireless Application Protocol) which govern the data transmissions between mobile stations and a remote gateway (generally called WAP gateway or WAP Gateway).
• WAP protocols for Wireless Application Protocol
• WAP gateway for Wireless Application Protocol
• Figure 1 depicts s 'chématiquement communication within a mobile station 10 consists of a mobile equipment ME, a phone in the example,' and a SIM chipcard.
• the mobile station 10 can communicate with another mobile station 10 ′ or with a remote server 100.
• the SIM card makes it possible to obtain a subscriber identification and a key in order to allow on the one hand the authentication of the subscriber on the GSM network, and on the other hand (de) encryption of the data (received) sent.
• the SIM card also allows the subscriber to access data specific to the GSM network as well as information on accessible services.
• the communication between the SIM card and the ME mobile equipment is governed by the BIP protocol (Bearer Independent Protocol) which is an option of the ETSI standard "GSM 11.14" describing the SIM Tool Kit (SKT) and which defines a set of commands and situations.
• BIP protocol allows the SIM card to use the communication means of the ME mobile equipment whatever the communication technology used.
• the communication protocols are generally all organized in several superimposed layers. A conventional configuration consists of a network layer which rests on a physical and link layer and which supports a transport layer, other layers which can be added, such as security, transaction, session, application or other, depending on the protocols considered.
• IP Internet Protocol
• TCP Transmission Control Protocol
• UDP User Datagram Protocol
• WDP Wi-Fi Datagram Protocol
• UDP or WDP transport protocols are unconnected mode protocols and are not considered reliable because they do not guarantee control of data transfer. Due to their simplicity, however, they have the advantage of allowing rapid transmission.
• UDP or WDP transport protocols act as simple data packet multiplexer / demultiplexer. These two transport protocols are very similar in their characteristics, even identical in the case of certain types of link (GPRS, CSD).
• MDS is a restriction of the transport layer • (of the UDP layer for example) of the maximum number of data bytes that can be accepted in the transmission of a single data packet (a datagram). If a message has more bytes than the size of the MDS, the transport layer destroys it without transmitting it to the upper layers or segments it into a plurality of data packets that the receiver cannot reconstruct.
• FIG. 2 illustrates the structure of a message M.
• Each message M includes a header H and information P (or payload in English).
• the header H is necessary to indicate the length of the message and its composition (for example a request to determine the MDS).
• FIG. 3 illustrates the principle of the segmentation of a message M by the UDP transport layer.
• the message M will be split into a plurality of data packets D (datagrams) the size of the MDS. " Each packet D then has a header which does not allow, when it reaches its destination, to assemble it with the other packets to reconstruct the message M. This reconstitution is indeed not guaranteed by the UDP protocol of the layer of transport.
• the objective of the invention is to propose a method of transmitting data in unconnected mode including a step of determining the size of the MDS in order to eliminate any risk of alienation or rejection of the transmitted data.
• the invention relates more specifically to a data transmission method according to a communication protocol from a mobile station composed of a smart card (SIM) associated with a host mobile device, said protocol being organized in several layers including at at least one datagram type data transport layer capable of transmitting data packets of maximum size (Maximum Datagram Size, MDS) in its entirety, characterized in that said transmission method comprises a step consisting, for the card (SIM) , determining the value of said maximum size of data packets (MDS) that can be fully transmitted by the transport layer of its host mobile equipment.
• the value of the maximum size of the data packets (MDS) is supplied to the card (SIM) directly by its mobile host equipment.
• the value of the maximum size of the data packets is determined by the card (SIM) from the transmission of at least one message exchanged between the. mobile station card and a computing entity, said messages being of different lengths when their number is greater than or equal to two.
• the determination of the value of the maximum size of the data packets (MDS) by a calculation entity is determined by the following steps: transmission of N messages by the SIM card comprising. each a specific header indicating at least one request for determining the maximum size of the data packets (MDS); filtering, by the mobile equipment transport layer, the lower length messages or equal to the maximum size of paquets.de data (MDS) - Acceptance 'sdits filtered messages retaining the header original specific and calculation of their respective length by the calculation entity; transmission of said calculated lengths to the card of the mobile station; determination of the value of said maximum size of data packets (MDS) by the card (SIM) by comparison of said calculated lengths.
• the calculation entity is included in the smart card or in a remote server able to communicate with the mobile station.
• the filtering of the transport layer consists in rejecting messages of length exceeding the maximum size of the data packets (MDS).
• the filtering of the transport layer consists in segmenting the messages of length exceeding the maximum size of the data packets (MDS) into a plurality of data packets of which only one retains the specific header. of the original message.
• MDS maximum size of the data packets
• the transport layer protocol is the User Datagram Protocol (UDP).
• UDP User Datagram Protocol
• the present invention also relates to a card 'chip (SIM) able to cooperate with a host mobile equipment for communication according to a protocol comprising a number of layers of which at least one datagram type of data transport layer capable of fully transmitting packets of data of a maximum size (Maximum Datagram Size, MDS), characterized in that said card (SIM) comprises means capable of extracting the value of said maximum size of data packets (MDS) which can be fully transmitted by the transport layer of its host mobile equipment.
• SIM card 'chip
• FIG. 1, already described illustrates the interface between a SIM card a mobile station
• FIG. 2, already described is a diagram of an example of the structure of a message to be transmitted
• FIG. 3, already described illustrates the principle of the segmentation of a message by the transport layer
• Figure 4 is a diagram of a first embodiment of the method according to the invention
• Figure 5 is a diagram of a second embodiment in "out the method according to the invention
• the objective of the present invention is to determine the . value of the maximum size of data packets that can be transmitted by the transport layer of mobile equipment.
• MDS will designate this value to be determined.
• the SIM card thus comprises means capable of determining this value of the MDS and can then conserve its memory, in particular as long as it does not detect a change in its host equipment.
• the value of the MDS is supplied to the SIM card directly by its host mobile equipment, for example when the mobile station is powered up, via a command compatible with the SKT standard, by example the TERMINAL PROFILE command.
• the value of the MDS is determined by calculation.
• FIGS. 4 and 5 illustrate the data exchanges between a mobile station 10 and a computation entity 50 within the framework of a determination of the value of the MDS.
• the computation entity 50 may be a remote server capable of communicating with a mobile station (such as an OTA server mentioned previously) or the mobile station itself or another mobile station.
• the calculation entity 50 can therefore be located in the SIM card itself in the form of an application for example, the SIM card sending loopback messages to the address of its equipment. host mobile (address of type 127. xxx within the framework of the IP protocol).
• the transport layer cannot transmit a message whose length is greater than its MDS.
• the transport layer rejects messages that are too long ( Figure 4) or segments them ( Figure 5).
• at least one segmented data packet will be the size of the MDS.
• the mobile station 10 will transmit a plurality of N messages M N of different length, predefined or not, intended for the calculation entity 50.
• N may be equal to 1, that is to say that only message M is transmitted between the SIM card of the mobile station 10 and the calculation entity 50.
• the message M is chosen to be very long so that it is certainly segmented by the transport layer of the equipment.
• mobile ME mobile ME.
• a plurality of messages M N are exchanged, with N being able to be fixed between 2 and 6, or even more if necessary, depending on the performance and / or • capacities of the SIM card.
• the header H N of each message M N ' must include information which should allow and facilitate the calculation of the MDS.
• the header H N must contain the information according to which the message is a request for computation of the MDS as well as possibly another field C whose bytes cannot all be equal to OxFF (this is to say all the bits to ⁇ l ').
• the useful information (payload) of these M N messages is however fixed with. all bits at ⁇ l ', ie all bytes at OxFF.
• the transport layer filters the messages Mj whose length is less than or equal to its MDS to transmit them in full and rejects or segments the others.
• the calculation entity 50 receives messages Mi having passed through the transport layer of the transmitting mobile equipment ME and selects those which have kept their original header H N comprising the request for determining the MDS ' .
• the calculation unit 50 For each received message Mi, the calculation unit 50 will then calculate a corresponding MDS as being the length L ⁇ of said received message Mi. The calculation entity 50 then goes. transmit these calculated Li lengths corresponding to the Mi messages received destined for the SIM card which will compare these Li lengths and keep the greatest value. The mobile station's SIM card can then adapt the length of its messages subsequent to the length of the MDS for reliable communication.
• said server can detect an anomaly of the MDS if it receives a message whose length is not that indicated in the header of said message. It can then alert the SIM card of the mobile station so that it initiates a (new) determination of the MDS.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)
• Credit Cards Or The Like (AREA)
• Radar Systems Or Details Thereof (AREA)

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• 2001
  • 2001-04-09 FR FR0104828A patent/FR2823408B1/fr not_active Expired - Fee Related
• 2002
  • 2002-03-22 AT AT02720069T patent/ATE405068T1/de not_active IP Right Cessation
  • 2002-03-22 US US10/474,483 patent/US7742500B2/en not_active Expired - Fee Related
  • 2002-03-22 WO PCT/FR2002/001012 patent/WO2002082748A1/fr active IP Right Grant
  • 2002-03-22 EP EP02720069A patent/EP1386453B1/de not_active Expired - Lifetime
  • 2002-03-22 DE DE60228228T patent/DE60228228D1/de not_active Expired - Lifetime

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